Brian O'Driscoll will definitely start for Ireland in their RBS 6 Nations opener against Italy at Croke Park.

Reports in the Irish media had suggested the Leinster centre was a doubt having sustained a quad muscle injury in training earlier this week.

But O'Driscoll gave a brief "yeah" when asked if he would be fit to take his place for the opening leg of Ireland's bid for back-to-back Grand Slams.

It is welcome news for Ireland coach Declan Kidney who was forced to withdraw Donncha O'Callaghan from his starting line-up yesterday after a knee injury sidelined the Munster lock.

As a result, Leinster's Leo Cullen comes in to make his first Six Nations start in seven years and Kidney is happy to have the captain of the Heineken Cup-holders on board.

Kidney said: "Leo has been in or around the squad for a long time. You are always delighted when a guy gets a go, especially when he has stuck it out as long as he has since his last Six Nations game.

"I know Leo from coaching the Irish Under-19s, which goes back a few years now. He is an exceptional leader and his reading of the game, on top of all of the other things he brings to it, will be an asset I think he will bring into the team.

"You always look to see what a guy will bring into a team as against what you are losing the day before a match.

"Bangs and knocks are part and parcel of it - that's why squads are so important. If you are waiting around for the same 15 to be fit all of the time that will never happen.

"We are lucky now that we have a lot of fellas who can slot in and out.

"It was disappointing for Donncha (O'Callaghan) but it is great for Donnacha Ryan, who steps up to the bench, with Leo getting the chance. Sometimes you make changes for the sake of it and sometimes they are a little bit pushed on you.

"We are looking forward to him playing and I think the enthusiasm he has brought into playing and the fact that Donncha (O'Callaghan) wasn't able to train in the past week and that Leo has been in the team (training anyway) means it has been pretty seamless really."

Those are sentiments echoed by Cullen's Leinster and Ireland team-mate O'Driscoll.

"He's the sort of guy who doesn't speak for the sake of it but very much when he does speak, people listen to him," said O'Driscoll.

"He chooses his thoughts and what he says very carefully and I think that's a great trait in a captain too.

"We'll certainly enjoy his leadership at the weekend. We know what he brings to a team - he's a bit of a nightmare to play against, so Italy will certainly find him tough to deal with."